1. Field of the Invention
The present invention relates to a rear air conditioner for a vehicle, and more particularly, to a rear air conditioner for a vehicle, which can prevent a decrease of air volume and improve mixing of cold air and hot air.
2. Background Art
In general, a rear air conditioner for a vehicle is applied to vehicles of a large capacity, Recreational Vehicles (RVs), or Sports Utility Vehicles (SUVs) as large as only a front air conditioner cannot agreeably cool or heat the inside of the vehicle. The rear air conditioner is installed in a sealed space of the rear of the vehicle in link with the front air conditioner, and so, constitutes a dual air conditioner together with the front air conditioner.
Such rear air conditioner is partitioned into two kinds: one having just an evaporator used for cooling the indoor; and the other having an evaporator and a heater core for cooling and heating the indoor. Furthermore, in the latter, the rear air conditioner is partitioned into a non air mixing type air conditioner and an air mixing type air conditioner.
In the non air mixing type air conditioner, an air discharge mode will be described as follows. Cold air is discharged only through a face vent when a cooling mode is operated, but hot air is discharged only through a floor vent when a heating mode is operated. That is, cold air and hot air are not discharged in a mixed state.
Moreover, the air mixing type air conditioner further includes a temperature control door for controlling opening and closing of a cold air passageway and a hot air passageway is disposed between the evaporator and the heater core. Now, an air discharge mode will be described as follows. According to control of the temperature control door, cold air and hot air are mixed with each other at the rear of the cold air passageway and the hot air passageway, and then, the mixed air is discharged to the inside of the vehicle through the opened vent or cold air or hot air is discharged to the inside of the vehicle through the vent according to opening an closing of the cold air passageway and the hot air passageway. That is, the air mixing type air conditioner can be operated in a bi-level mode.
FIG. 1 shows an example of the air mixing type rear air conditioner. The air mixing type rear air conditioner includes: a blower 10 having a scroll case 12 and a centrifugal fan 14 rotatably mounted inside the scroll case 12; an air conditioning case 40 connected with the blower 10 and having a face vent 42 and a floor vent 44 formed at an outlet thereof, and a vent door 46 for controlling opening and closing of the face vent 42 and the floor vent 44; an evaporator 20 and a heater core 30 embedded in the air conditioning case 40; and a temperature control door 50 for controlling opening and closing of a cold air passageway (P1) and a hot air passageway (P2) of the air conditioning case 40.
When the centrifugal fan 14 is rotated by a blast motor (not shown), air is inhaled in an axial direction of the centrifugal fan 14 through an air inlet (not shown) of the blower 10, and then, discharged in a radius direction of the centrifugal fan 14 and induced into the air conditioning case 40. The air induced into the air conditioning case 40 passes through the evaporator 20, and then, flows toward a mixing zone (MZ) of an air outlet of the air conditioning case 40 through the cold air passageway (P1) or the hot air passageway (P2) opened according to opening and closing by the temperature control door 50. When the air passes through the hot air passageway (P2), the air is heated by the heater core 30, and so, changed into hot air.
Therefore, as shown in FIG. 1, when the temperature control door 50 is turned to a neutral zone in order to open both of the cold air passageway (P1) and the hot air passageway (P2), cold air flows to the mixing zone (MZ) through the cold air passageway (P1), and hot air flows to the mixing zone (MZ) through the hot air passageway (P2). After that, cold air and hot air are mixed with each other in the mixing zone (MZ), and then, the mixed air is discharged to the inside of the vehicle through the opened vent.
However, in the conventional air mixing type rear air conditioner for vehicle, a space for mixing air in the mixing zone (MZ) must be secured sufficiently. But, the conventional air mixing type rear air conditioner has a problem in that it is difficult to secure the space larger than that of the non air mixing type rear air conditioner due to a special limitation of the vehicle and to sufficiently secure the mixing zone since the inside layout of the vehicle is restricted. Therefore, in view of the recent trend of compact-sized rear air conditioners, it is also difficult to make the rear air conditioner compact due to the special problem of the mixing zone. Additionally, the floor vent 44 causes a problem in air mixing since it is mounted near to the hot air passageway (P2), and so, temperature of the air discharged to the floor vent 44 is excessively higher than temperature of the air discharged to the face vent 42. On the contrary, if temperature of the air discharged to the face vent 42 is higher than temperature of the air discharged to the floor vent 44, passengers may feel unpleasantness. Furthermore, according to kinds of vehicles and the internal shapes of the air conditioning case 40, the conventional rear air conditioner may cause lots of trials and errors in keeping temperature of the air discharged to the face vent 42 and the floor vent 44 in a predetermined level.
Therefore, it may be considered to reduce a size of the vent door 46 to sufficiently secure the space of the mixing zone (MZ) for achieving good mixing of hot air and cold air. However, in this case, air volume and noise reduction efficiency are reduced due to air resistance since a sectional area of the passageways of the face vent 42 and the floor vent 44.